drivers/serial/usart_mcux_lpc.c

/*
 * Copyright (c) 2017, NXP
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/** @file
 * @brief USART driver for LPC54XXX family
 *
 * Note:
 * - Only basic USART features sufficient to support printf functionality
 *   are currently implemented.
 * - The driver works only in polling mode, interrupt mode is not implemented.
 */

#include <errno.h>
#include <device.h>
#include <uart.h>
#include <fsl_usart.h>
#include <fsl_clock.h>
#include <soc.h>
#include <fsl_device_registers.h>

struct usart_mcux_lpc_config {
	USART_Type *base;
	clock_name_t clock_source;
	u32_t baud_rate;
};

struct usart_mcux_lpc_data {
	/* put irq call back instance when required */
};

static int usart_mcux_lpc_poll_in(struct device *dev, unsigned char *c)
{
	const struct usart_mcux_lpc_config *config = dev->config->config_info;
	u32_t flags = USART_GetStatusFlags(config->base);
	int ret = -1;

	if (flags & kUSART_RxFifoFullFlag) {
		*c = USART_ReadByte(config->base);
		ret = 0;
	}

	return ret;
}

static void usart_mcux_lpc_poll_out(struct device *dev,
					     unsigned char c)
{
	const struct usart_mcux_lpc_config *config = dev->config->config_info;

	/* Wait until space is available in TX FIFO */
	while (!(USART_GetStatusFlags(config->base) & kUSART_TxFifoEmptyFlag))
		;

	USART_WriteByte(config->base, c);
}

static int usart_mcux_lpc_err_check(struct device *dev)
{
	const struct usart_mcux_lpc_config *config = dev->config->config_info;
	u32_t flags = USART_GetStatusFlags(config->base);
	int err = 0;

	if (flags & kStatus_USART_RxRingBufferOverrun) {
		err |= UART_ERROR_OVERRUN;
	}

	if (flags & kStatus_USART_ParityError) {
		err |= UART_ERROR_PARITY;
	}

	if (flags & kStatus_USART_FramingError) {
		err |= UART_ERROR_FRAMING;
	}

	USART_ClearStatusFlags(config->base,
			       kStatus_USART_RxRingBufferOverrun |
			       kStatus_USART_ParityError |
			       kStatus_USART_FramingError);

	return err;
}

static int usart_mcux_lpc_init(struct device *dev)
{
	const struct usart_mcux_lpc_config *config = dev->config->config_info;
	usart_config_t usart_config;
	u32_t clock_freq;

	clock_freq = CLOCK_GetFreq(config->clock_source);

	USART_GetDefaultConfig(&usart_config);
	usart_config.enableTx = true;
	usart_config.enableRx = true;
	usart_config.baudRate_Bps = config->baud_rate;

	USART_Init(config->base, &usart_config, clock_freq);

	return 0;
}

static const struct uart_driver_api usart_mcux_lpc_driver_api = {
	.poll_in = usart_mcux_lpc_poll_in,
	.poll_out = usart_mcux_lpc_poll_out,
	.err_check = usart_mcux_lpc_err_check,
};

#ifdef CONFIG_USART_MCUX_LPC_0
static const struct usart_mcux_lpc_config usart_mcux_lpc_0_config = {
	.base = (USART_Type *)DT_USART_MCUX_LPC_0_BASE_ADDRESS,
	.clock_source = kCLOCK_Flexcomm0,
	.baud_rate = DT_USART_MCUX_LPC_0_BAUD_RATE,
};

static struct usart_mcux_lpc_data usart_mcux_lpc_0_data;

DEVICE_AND_API_INIT(usart_0, DT_USART_MCUX_LPC_0_NAME,
		    &usart_mcux_lpc_init,
		    &usart_mcux_lpc_0_data, &usart_mcux_lpc_0_config,
		    PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
		    &usart_mcux_lpc_driver_api);
#endif /* CONFIG_USART_MCUX_LPC_0 */